Answer:
The Tax Code
Step-by-step explanation:
A tax code is a string of letters and numbers that tells HMRC how much tax one should be paying. The standard code for the year 2018/19 is 1185L. Usually all of the options given are somehow effecting the position on immigration of any country but the tax code is something that is not that much important. People usually make immigration to search for a better life but the taxes in the new country effect them. But these taxes do not effect the overall immigration procedure and image of the country so option A is the correct option.